Band-saw mill



(No Model.) 2 sheetssheet 1.

` DE WITT G. PRBSCOTT.

BAND SAW MILL.

No. 369,81. Patented Sept, 13, 1.887.

(No Model.) DE WITT C. PRESCOTT. 2 'Sheets-Sheet 2.

BAND SAW MILL.

No. 369,881. Patented Sept.- 13, 1887.

l. .im A

II ...Bill- Nv PETERS. Pham-Limogmpher, wagmngmn, D. C.

ilNrTnn STATES PATENT einen.,

BAND-SAW IVIILL.

SPECIFICATION forming part of Letters Patent No. 369,881, dated September 13, 1887.

Application filed February 23, 1887. Serial No. 229,599. (No model.)

.To all whom t may concer-n:

Beit known that I, DE WITT CLINTON Pans- COTT, a citizen of the United States,residing at Marinette,in the county of Marinette and State of Wisconsin, have invented certain new and useful Improvementsin Band-Saw Mills, which are fully set forth in the following specification, reference being had to the accompanying drawings, in which- Figure 1 represents a front elevation of the upright portion of a band-saw mill containing my improvements and showing the mounting of the upper band-wheel, said wheel being largely broken away; Fig. 2, a verticalsection of the same, taken on the line mx, Fig. 1; Fig. 3, a detail plan section taken on the liney y, Fig. 2; Fig. 4, a similar view taken on the line c z, Fig.2; Fig. 5, a similar view taken on the line a u, Fig. 2; and Fig. 6, an illustrative elevation showing the relation of a band-saw, its wheels, and the log when the mill is in operation, this last figure not being made, however, on any particular scale.

My invention relates to that class of sawmills called band-mills, and may be said to be an improvement upon the mill shown and described in my prior application, Serial No. 207,142, led July 3, 1886. l

The object of the present invention is to pro vide for adjusting the upper band-wheel and to make the adjusting device exceedingly sensitive, so that the`slightest change in strain will effect a movement of the said wheel,therc by taking up even slight slack almost instantly and keeping the saw always under proper strain.

I will proceed to describe one way in which I have carried out my invention in practical form, and will then point out denitely in the claims the special improvements which I believe to be new and wish to protect by Letters Patent. y

The mill may be in its main features substantially like that shown in my said prior application, and for this reason I have not shown in the drawings the entire structure, nor shall I attempt to describe it in the present case. At the same time I desire to say that the present improvements are not applicable alone to a mill constructed upon the plan described and shown in the said prior application, butA may be applied to other structures, with, perhaps, such slight modifications as may be necessary to adapt the devices to differences in the main portions of the mill.

In the drawings, A represents the base, upon which is mounted a hollow column, B, which constitutes the upright portion of the main frame. This column, as in my former case, consists of two parts-a lower section, b,which is fastened permanently to the base, and is therefore stationary, and an upper section, b,which is telescoped upon the upper portion of the stationary part b and is movable vertically thereon. In my former structure, referred to above, this upper section has appeared in the form of a closed cap; butin the present instance I leave both ends of this section open, so that ready access may be had to the inte' rior of the upper end of the column. A bracket, a, is secured to the stationary portion of the column and constitutes a hanger for one end of the shaft c of the lower band- Wheel, C. The lower portion of the stationary part of the columniis enlarged somewhat, at least on one side thereof, and in this portion, near the base, is cut a man-hole, b2, as shown in Fig. 2 of the drawings, whereby access may be had to the interior of the column at its base. The upper or movable section of the column is supported by a strong short post, b3, which is threaded, and enters a suitably-threaded socket or nut, c', in the upper portion of the hanger a. The upperend of the post is journaled in a cross-piece or any suitable projection on the lower end of the movable part b', and may be turned by a handlever, b4, for the purpose of adjusting the movable section Z1', this post operating as a sort of j ackscrew for the purpose. It will be noticed that in the drawings this supporting vdevice is located in front of the column. This arrangement is desirable, because the upper bandwheel is also located on the same side of the column, so that here is the greater weight, and the location of the support here will be very nearly at the middle of the entire weight on the section b', quite sufficiently near for practical purposes. A bracket, D, is .attached to the lower end of the movable section b. This bracket projects outward horizontally a short distance from the column, and is then turned ICO - posed of two bars bolted together.

upward at a right angle, being projected up about as high as the upper end of the section to which it is attached. It is hollow and open at each end. At the lower end of the bracket, where it is attached to the section b', a slot, d, is cut in the latter, and a similar slot, d, in the stationary section b, thereby providing an opening from the bracket into the column, and at the elbow of the bracket a slot, cl2, is cut, being arranged about opposite to the opening din the column. Just outside of the elbow and on each side of the slot d2 are lugs di.

At the upper end of the movable section b a sleeve bracket, E, is attached, being arranged at the back side of the column or opposite to and in line with the vertical portion of the bracket D. At the lower end of this same movable section, and immediately below the sleeve E, are two horizontal lugs, e, vattached to the section and about opposite tothe horizontal member of the bracket D. Aslot, e', is cut in the section b between these lastnamed lugs, and a similar slot, e2, in the stationary section b, for the purpose which will be described presently.

rIhe upper band-wheel, F, is secured to a shaft, f, which is mounted in boxes f. These boxes are in turn mounted upon bearingblocks G and G, the former at the front and the latter at the rear of the column. The bearing-blocks are provided with yokes g, within which thejournal-boxes are set and secured by pivot-pins g', which pins are threaded, so as to be adj ustable. The front bearing-block terminates below in a stem, g2, which is adapted to fit the upper open end of the bracket D and to slide up and down therein. Therear bearing-block terminates in asimilar stem, g3, which is adapted to fit the sleeve E and move vertically therein. A lever, H, is pivoted at one end to the lugs di on the bracket D, and extends inward horizontally through this bracket and the walls of the column into the interior of the latter. A similar lever, I, is pivoted at one end. to the lugs e on the other side of the column, and is extended inward horizontally through the slots in the column into the interior of the latter. The inner ends of these levers are pivoted to the lower end of a connecting-rod, J, inside of the column, the upper end of which is pivoted to the short arm of a lever, K, which is also pivoted to a lug, 7c, on the inside of the upper end of the movable section of the column. This lug is arranged on the side of the column next to the band-wheel, and the lever K extends across nearly to the other side of the column.

As shown in the drawings, the lever H is a single bar, while I and K are double, or com- This is a mere detail of construct-ion, however, as a inatter of convenience. A supporting post or rod, h, is attached at its upper end to the stem g2 of the front bearing-block by a screw-thread connection. The lower end of this supportingrod rests upon the lever H a short distance in front of its pivot, and in order to make the device sensitive I prefer vto construct the lower end of the rod with a knife-edge, h', so as to make a knife-edge bearing for the support of the front journal of the upper band-wheel. A similar post or rod, t', is attached by a screwthread connection to the stem g3 of the rear bearing-block, and at its lower end is connected by a hinge-joint to the lever I a short distance in front of its pivot. For convenience this post may be divided, as shown in Fig. l of the drawings, and provided with a nut and ratchet device, L, for the purpose of adjusting the length of the rod, the upper section of which can, of course, be turned, while th-e lower one cannot. The device, as shown in the drawings, consists of a sleevenut, Z, threaded right and left at its opposite ends. This nut receives the ends of the respective sections of the post, which are threaded right'and left for this purpose. The nut is provided with external teeth around its center, with which an ordinary ratchet-lever, Z, is arranged to engage, thereby providing an ordinary and well-known device for turning the nut. Obviously the turning of the nut in one direction will force the sections of the support apart, while turning in the other will draw them together, by which operation the rear end of the shaft may be adjusted to bring the shaft into a level position. Any other suitable device may be used for this particular nut for this purpose. The post h is also adj usted suitably in a similar' way by turning it in its threaded socket; but as it is not positively connected to the lever at its lower end it is not necessary to divide it.

It is obvious that any vibration of the lever K will cause a vibration of the levers H and I, and consequentlyasimultaneous adjustment of the two bearing-blocks of the upper bandwheel shaft in a vertical direction. The distance from the outer pivots of the levers H and I to the common pivot at their inner ends within the column is practically the same, as is also the distance between each outer pivot and the bearing-point of the respective supportingposts upon their respective levers; hence the vertical movement of the bearingblocks and the journals which they support will be practically the same. It will be seen that if the outer or long arm of the lever K be drawn downward the inner or short arm ICO IIO

will be raised, thereby pulling upward the introduced through the man-hole in the base portion of the column, this hole being made mainly for the purpose of placing and removingtheseweights. Thisalso permitstheweight to be readily increased or diminished, as may be desired. Obviously by this arrangement of levers and weights the shaft of the upper band-wheel is held upward constantly, so as to keep the saw taut upon its wheels, and it is evident from the arrangement ofthe levers that the adjusting device is very sensitive, so that the least little slack in the saw will be taken up and the latter maintained in that taut condition which is necessary for its satisfactory operation.

I am aware that the lower band-wheel in mills of this type has been made adjustable automatically for the purpose of taking up slack. There is, however, an objection to this latter-mode of adjustment, which will be eX- plained by reference to Fig. 6 of the drawings. In this figure, N represents the lower bandwheel, O the upper wheel, and l? the saw, these wheels and the saw running in the direction indicated by arrows. A portion, Q, of the logcarriage is also shown with a log, R, thereon and the saw in operation. Guides pp for the saw are arranged as usual, one above and one below the log. Now the momentum of the wheel produces whatis known as overthrow of the saw as the latter runs over to the front from the upper wheel. This overthrow produces a slight slack in the saw between the point where it leaves the upper band-wheel and the point where it enters the log-that is, between'the points indicated by l and 2 in Fig. 6 of the drawings. It is not serious, but sufficient to destroy the proper action of the saw. Vhen the adjustment for taking up slack is made at the lower band-wheel, this overthrow slack must be taken up by pulling the saw back over the upper band-wheel and in opposition to the action of said Wheel, for of'course it cannot be taken up down through the log While the saw is at work.

. This action brings an additional strain upon the back portion of the saw and greatly increases the danger of breaking. With the present improvement, whereby the upper band-wheel is made automatically adjustable, it must be obvious that this objection is entirely overcome, for the upward movement o f the wheel will take up the overthrow slack immediately and directly. The same remark applies also to the back portion of the saw, for the action is equally direct on that side of the wheel, so that this adjustment of the upper band-wheel takes the slack on both sides directly, thereby preventing eXtra strain upon the saw, and at the same time keeping the latter perfectly taut while in operation.

The proper leveling of the shaft of the upper band-wheel is effected byithe adjusting device at the back of the column, whereby the connecting-rod i is made adjustable in length. The alignment of this wheel, to bring it into thesame plane with the lower wheel, is effected by means of the pivot-boxes in which the shaft is journaled. The pivots being threaded, the boxes may be set back and forth in a horizontal direction to perfect the adjustment of the wheel to its proper plane.

I do not wish to be understood as limiting my invention to the precise devices which are herein shown and described. The upper bandwheel shaft may be made automatically adjustable by other devices, and as this is the main characteristic of my invention, I claim it broadly. The special construction and arrangement ofthe devices which I here employ to secure the adjustment of the said shaft may be varied without materially departing from the improvement asit is here shown embodied. Such modifications may be made without interfering with the invention, and will very likely be required in applying the invention to a band-mill having a supporting-frame different from that herein set forth.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In a band-saw mill, the upper band-Wheel shaft,- in combination with independent vertically-movable bearings, in which the ends ot' said shaft are separately mounted, and auto mat-ic adjusting mechanism applied to each of the bearings of said shaft, substantially as and for the purposes specified.

2. In aband-saw mill, the verticallyadjustable column-section b', in combination with vertically-adjustable bearings for the upper bandwheel shaft mounted on said movable section, and automaticadjusting mechanism applied to said bearings, whereby the upper band-wheel is adjusted, substantially as and for the purposes specified.

3. In a band-saw mill, the horizontal levers H and I, pivoted to the supporting-frame and extending inward toward each other, in combination with the upper band-wheel shaft, vertically-adjustable bearings for said shaft, supports for said bearings sustained at their lower ends by said levers, respectively, and an automatic device applied to the inner ends of said levers and continuously operating to draw them upward, substantially as and for the purposes specified.

. 4. In a band-saw mill, the horizontal levers H and I, pivoted to the supporting-frame, in combination with the vertically-movable bearings of the upper band-wheel shaft supported by said levers, the lever K, connecting-rod J, and weight m, applied to t-he lever K, subA stantially as and for the purposes specified.

ITO

5. The upright hollow column, in combina* 6. The upper band-wheel shaft, in combination With the bearing-blocks G and G', terminating in stems, substantially as specified, the sleeve-supports D and E, adapted to re- Ceive the stems of said blocks, the supportingrods h and z', and the supporting and adjusting levers H and l, substantially as and for the purposes specified.

7. The hollow column B, composed of stationary section b and movable section b', provided With vertical registering slots therein, substantially as speeied, in combination With the adj usting-levers H and I, pivoted to the movable section b and extending inward through said slots to the interior of the eolumn, the vertically-adjustable bearings of the upper band-Wheel shaft,supported by said 1evers, and a Weight applied to the inner ends 0f said levers to'eonstantly pull them upward, substantially as and for the purposes specified.

8. The supporting and adjusting levers H and I, in combination with the upper band- Wheel shaft, the bearing-blocks for said shaft, the front supporting-post, h, resting on the lever H with a knife-edge bearing, and the rear supporting-post, i, divided as described, and pivoted to the lever I, and a threaded nut applied to the free ends of the sections,

whereby they may be moved to and from each other, substantially as and for the purposes speeiiied.

DE WITT CLNTON PRESCOTT.

Witnesses:

JOHN J. ANDREW,

P. MARS. 

